This invention relates to a driving method for moving a healed frame up and down in negative dobby machines or negative cam machines installed to looms.
In the prior art, when a resilient transmission member such as a rope connected to a shedding lever of a negative dobby machine or cam machine is disposed above a heald frame, the heald frame driving method is performed by raising the heald frame using tension of the rope and depressing it using spring restoring force. In this driving method, however, for example, when spun yarn fabric is woven in refined clothing fashion, if the tension of the downward warp is made larger than that of the upward warp, spring tension must be increased. Since the heald frame is raised against the above mentioned spring tension, a large force acts on the rope and on the negative dobby machine body or the negative cam machine body, thereby abrasion is increased in such part and power is lost. Moreover, since the spring and related members are disposed below the heald frame, maintenance is inconvenient and operability is not favorable.